The printed circuit board (PCB) is an important electronic device. It is one of the most important components in the electronic industry. The PCB is utilized in almost all kinds of electronic devices, for example, electronic watch, calculator, computer, communication electronic device, military weapon system etc., for electrically connecting the electronic components (e.g., integrated circuit) thereof. Thus, the PCB plays a more and more important role in the circuit technique field. Now the size of the electronic device has become smaller and smaller, and the function of the electronic deuce has been unproved. Since more electronic components are installed in a small space, heat emitting of the circuit may increase. Therefore, it is necessary to find a solution to solve the cooling problem of the circuit.